kicad-developers team mailing list archive

[Jean-Paul Louis <louijp@xxxxxxxxx>]

I agree strongly with Nick. A DXF import for the PCB outline is a must have, 
not just a nice to have.
During my professional life, I always pushed the PCB design center to import
the PCB outline from the mechanical design.

My $0.02,
Jean-Paul
AC9GH

> On Jun 15, 2015, at 3:54 AM, Nick Østergaard <oe.nick@xxxxxxxxx> wrote:
> 
> I am not quite sure where you are going with this mail, but I agree
> that DXF import is a good way to get complex board shapes in pcbnew.
> The drawing tools are sort of limited at the time of writing.
> 
> But often when you need a complex board shape it is because you are
> constrained by the end product somehow, and it does not make much
> sense to draw the board shape in KiCad itself.  So good support for
> DXF import is important.
> 
> 2015-06-15 3:39 GMT+02:00 Cirilo Bernardo <cirilo.bernardo@xxxxxxxxx>:
>> Lately I have seen more people asking about board shapes which are
>> not easily described by a small number of line segments and circular
>> arcs, and Jean-Pierre mentioned STEP Import for a board shape. I
>> think the best mechanism for complex board shapes will remain the
>> DXF format since STEP (or even IGES) can contain so much
>> information and it is impossible to guess the design intent; however
>> many MCADs will create a DXF outline which will make use of
>> circular arcs, line segments, ellipses, Rational Polynomial Curves,
>> NURBS, and occasionally even Bezier curves. I would suggest that
>> rather than think of attempting to import a board outline + cutouts +
>> drill holes from STEP/IGES we should add to the features of the
>> DXF importer to support at least ellipses and rational polynomial
>> curves (which is what SolidWorks uses even for circular arcs) and
>> possibly 2D NURBS if anyone knows an MCAD that exports it in DXF.
>> 
>> The question of natively supporting RPCs and NURBS within KiCad
>> is something to consider in order to preserve such information
>> which is ultimately imported from MCADs, even if we never support
>> native tools to edit these entities. Who knows, maybe in the future
>> someone would like to use such features to describe a track shape
>> rather than generating an inefficient line segment approximation (oh,
>> the DRC nightmare).
>> 
>> In the (far) future there is also the PRC file specification which I think
>> would be very good to support. At the very least we can create
>> previews of STEP and IGES files for quick display and this would
>> also allow the eventual creation and decoding of 3D PDFs.  The
>> specification allows arbitrary metadata which in theory we can exploit
>> to ensure that KiCad knows what parts are outlines, cutouts, drill holes
>> (N/PTH) and we can have more unambiguous exchange of data; of
>> course every MCAD would need an exporter which could provide the
>> information in just the way KiCad wants, so this would not only be a
>> huge project but we can safely guarantee that DXF will remain the
>> best general solution.
>> 
>> - Cirilo
>> 
>> 
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